WASHINGTON — What happens when lava and water meet? Explosive experiments with manmade lava are helping to answer this important question.

An intense reaction occurs after water is injected into molten rock.Credit: Douglas Levere / University at Buffalo.

By cooking up 10-gallon batches of molten rock and injecting them with water, scientists at the University at Buffalo are shedding light on the basic physics of lava-water interactions, which are common in nature but poorly understood.

The first results from the project are published today in the Journal of Geophysical Research: Solid Earth, a journal of the American Geophysical Union. The scientists caution that the number of tests so far is small, so the team will need to conduct more experiments to draw firm conclusions.

The research shows that lava-water encounters can sometimes generate spontaneous explosions when there is at least about a foot of molten rock above the mixing point. In prior, smaller-scale studies that used about a coffee cup’s worth of lava, scientists in Germany found that they needed to apply an independent stimulus — in essence pricking the water within the lava — to trigger a blast.

The results reported in JGR: Solid Earth also point to some preliminary trends, showing that in a series of tests, larger, more brilliant reactions tended to occur when water rushed in more quickly and when lava was held in taller containers. (The team ran a total of 12 experiments in which water injection speeds ranged from about 6 to 30 feet per second, and in which lava was held in insulated steel boxes that ranged in height from about 8 to 18 inches.)

“If you think about a volcanic eruption, there are powerful forces at work, and it’s not a gentle thing,” said Ingo Sonder, a research scientist in the Center for Geohazards Studies at UB and lead author of the new study. “Our experiments are looking at the basic physics of what happens when water gets trapped inside molten rock.”

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